Distribution study of damage caused by the 2015 Mw7.8 Gorkha earthquake in Nepal

Abstract

The 2015 Mw7.8 Gorkha earthquake in Nepal resulted in 9,084 fatalities, the collapse of thousands of buildings, and a large number of landslides. Field investigations revealed the poor seismic performance of structures in the affected area, which can be categorized as self-built reinforced concrete frame structures, brick and concrete structures, brick and timber structures, and rubble structures. Interpretation of earthquake-induced landslides was conducted based on high-resolution satellite imagery. The landslides triggered by the Mw7.8 Gorkha earthquake were primarily distributed in the boundary area between the High Himalaya and the Low Himalaya, and basically spread along the Main Central Thrust (MCT). The distribution of landslides was consistent with the characteristics of topography, seismic intensity, and aftershocks. The intensity map of the Mw7.8 Gorkha earthquake was revised based on the investigation of building damage and secondary hazards. The overall intensity circle featuring two macro-seismic epicenters, appeared elliptical with a NWW orientation on the long axis, and a highest intensity reaching Ⅸ.